Dental and medical treatments and procedures

ABSTRACT

A method treating a root canal in a tooth by introducing into the pulp chamber of a tooth and pulsing a laser light into the fluid reservoir so as to disintegrate pulp within the root canal without generation of any significant heat in said liquid fluid so as to avoid elevating the temperature of any of the dentin, tooth, or other adjacent tissue more than about 5° C.

This Application is a continuation of application Ser. No. 14/537,742,filed Nov. 10, 2014, which is a continuation in part of application Ser.No. 14/077,880, filed Nov. 12, 2013, which is a continuation ofapplication Ser. No. 13/633,096, filed Oct. 1, 2012, which is acontinuation of application Ser. No. 12/875,565, filed Sep. 3, 2010,which is a continuation in part of application Ser. No. 11/895,404,filed Aug. 24, 2007, the entire contents of each of which areincorporated by reference herein. Application Ser. No. 12/875,565 isalso a continuation in part of application Ser. No. 12/395,643, filedFeb. 28, 2009, which is a continuation in part of application Ser. No.11/895,404, filed Aug. 24, 2007, the entire contents of each of whichare incorporated by reference herein. Application Ser. No. 12/395,643 isalso a continuation in part of application Ser. No. 11/704,655, filedFeb. 9, 2007, which claims priority to Provisional Application No.60/840,282, filed Aug. 24, 2006, the entire contents of each of whichare incorporated by reference herein. Application Ser. No. 11/895,404 isa continuation in part of application Ser. No. 11/704,655 and alsoclaims priority to Provisional Application No. 60/840,282, the entirecontents of each of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is related to the field of dentistry, medicine andveterinary medicine.

BACKGROUND OF THE INVENTION

In the field of dentistry, one of the most important and delicateprocedures is that of cleaning or extirpating a diseased root canal toprovide a cavity which is substantially free of diseased tissue andantiseptically prepared for a permanent embalming or obturation to sealoff the area. When done properly, this step enables subsequentsubstantially complete filling of the canal with biologically inert orrestorative material (i.e., obturation) 1, without entrapping noxioustissue in the canal that could lead to failure of the therapy.

In a typical root canal procedure, the sequence is extirpation ofdiseased tissue and debris from and adjacent the canal followed byobturation. Often there is an intermediate filling of the canal with acalcium hydroxide paste for sterilization and reduction of inflammationprior to obturation and final crowning. In performing the extirpationprocedure, the dentist must gain access to the entire canal, shaping itas appropriate. However, root canals often are very small in diameter,and they are sometimes quite curved with irregular dimensions andconfigurations. It is therefore often very difficult to gain access tothe full length of the canal and to properly work all surfaces of thecanal wall.

Many tools have been designed to perform the difficult task of cleaningand shaping root canals. Historically, dentists have used elongate,tapered endodontic files with helical cutting edges to remove the softand hard material from within and adjacent the root canal area, Suchroot canal dental procedures often result in overly aggressive drillingand filing away of otherwise healthy dentin wall or physical structureof the tooth root thereby unduly weakening the integrity or strength ofthe tooth. Additionally, when performing root canal procedures, it isdesirable to efficiently debride or render harmless all dead, damaged,or infected tissue and to kW all bacteria, viruses and/or otherundesirable biological material within the root canal system,Illustrations of a typical root canal system are shown in FIGS. 1A and1B. The mot canal system includes the main root canal 1 and many lateralor accessory canals 3 that branch off of the main canal 1, all of whichcan contain diseased or dead tissue, bacteria, etc. It is common duringroot canal procedure to mechanically strip out the main canal nerve,often tearing it away from the lateral canal nerves, much of which canthen stay in place in the canal and become the source of later trouble,Thereafter, the main canal 1 is cleaned and extirpated with a taperedfile. While it is desirable to extirpate all of the main and accessorycanals in a root canal system, some of the lateral canals 3 are verysmall and extremely difficult to reach in order to remove tissue. Suchlateral canals are often perpendicular to the main canal and may bend,twist, and change cross-section as they branch off from the main canal,making them practically inaccessible to extirpation with any known fileor other mechanical device. Accordingly, lateral canals are often notproperly extirpated or cleaned. Many times no effort is made in thisregard, relying instead on chemical destruction and embalming processesto seal off material remaining in these areas. This approach issometimes a source of catastrophic failure that can lead to loss of thetooth and other problems. Further, when the main canal is extirpatedwith a tapered file, this action can leave an undesirable smear layeralong the main canal which can plug some of the lateral canal openingsand cause other problems that trap noxious material against laterefforts to chemically disinfect the canal.

Dentists can attempt to chemo-mechanically debride and/or sterilize bothmain and lateral canals using a sodium hypochlorite solution or variousother medicaments that are left in the root canal system for 30 to 45minutes a time following primary mechanical extirpation of nerve andpulp tissue. However, this approach does not necessarily completelydebride or render harmless ail of the lateral root canals and materialtrapped therein because of the difficulty in cleaning off the smearlayer and/or negotiating and fully wetting the solution into some of thesmaller twisted lateral canals. As a result, many treatments using thismethod fail over time due to reoccurring pathology. This often requiresretreatment and sometimes loss of the tooth.

Attempts have been made to reduce or eliminate the use of endodonticfiles and associated drawbacks by using lasers in the performance ofroot canal therapy. Some of these approaches involve burning away orcarbonizing diseased and other tissue, bacteria, and the like within thecanal. In these approaches, laser light is said to be directed orfocused into or onto the diseased tissue, producing very hightemperatures that intensely burn, carbonize, ablate, and destroy thetissue. These ablative treatments using high thermal energy to removetissue often result in damage to the underlying collagen fibers anddentin of the root 5, even fusing the hydroxyapatite which makes up thedentin. In some cases, such treatments can cause substantial heating ofthe periodontal material and bone 7 surrounding the tooth, potentiallycausing necrosis of the bone and surrounding tissue. Additionally, thehigh temperatures in such treatments can melt the walls of the maincanal, often sealing off lateral canals, thereby preventing subsequenttreatment of lateral canals, Other attempts to use lasers fix root canaltherapy have focused laser light to a focal point within fluid disposedwithin a root canal to boil the fluid. The vaporizing fluid createsbubbles which erode material from the root canal when they implode. Suchtreatments which must raise the fluid temperature above the latent heatof vaporization significantly elevate the temperature of the fluid whichcan also melt portions of the main canal and cause thermal damage to theunderlying dentin, collagen, and periodontal tissue. The damage causedto the tooth structure by these high energy ablative laser treatmentsweakens the integrity or strength of the tooth, similar to endodontictreatment utilizing endodontic files.

Therefore, there is a present and continuing need for minimallyinvasive, biomemetic, dental and medical therapies which remove diseasedtissue and bacteria from the main root canal as well as the lateralcanals of the root canal system while leaving the biological structuresundamaged and substantially intact.

SUMMARY OF INVENTION

It is an object of the present invention to provide new medical, dentaland veterinary devices, treatments and procedures.

It is another object of the present invention to provide a device forproducing a photoacoustic wave used in endodontal treatment of toothinteriors comprising a laser system having a wavelength of at least 1500nm and power of at least 0.5 Watt, a sheath coupled at one end to thelaser system said sheath comprising a laser fiber optic and a treatmentfluid lumen, both running the length of the sheath and exiting thesheath at a distal end, said laser fiber optic having a flat, blunt ormodified tip and whereby inserting the tip into the treatment fluiddelivered into root canal produces a photoacoustic wave as the laser ispulsed.

It is yet another object of the present invention to provide a methodfor endodontal treatment of tooth interiors comprising the steps of:providing a laser having a wavelength of at least 1500 nm and at least0.5 Watt; providing a laser fiber optic coupled to the laser, said laserfiber optic having a flat, blunt or modified tip; inserting the tip ofthe laser fiber optic into a root canal in a tooth; treating theinterior root canal by creating a photoacoustic wave front in theinterior of the root canal using the at least 1500 nm at least 0.5 Wattlaser energy; withdrawing the tip of the laser fiber optic from the rootcanal; and sealing root canal.

In accordance with one embodiment of the present invention, a method isprovided for treating a root canal in a tooth containing a crown portionextending to above a gum line and one or more elongate roots integralwith and projecting from the crown into the gum and an adjacent jawbone. Each root has a root canal containing pulp including nerve andother tissue in open communication with a pulp or coronal chamber in thecrown. An opening is formed in the crown into the pulp chamberdimensioned to enable working access to a canal of said one or moreroots for treatment thereof. Pulp is removed from the pulp chamber toprovide an open area therein to gain access to pulp in said canal and,optionally, remove at least pan of the pulp from said canal to make anopening in said canal in flow communication with said open area in saidpulp chamber. Liquid containing hydroxyl groups is dispensed into atleast the open area in the pulp chamber in an amount sufficient toprovide a liquid reservoir.

A laser system is provided containing a source of a laser light beam andan elongate optical fiber connected to said source and configured totransmit said laser light beam to a tip portion thereof: The tip mayinclude a tapered tip tapering to an apex with a surrounding conicalwall, substantially the entire surface of which is uncovered so thatsaid laser light beam is emitted therefrom generally omnidirectionally,The optical fiber may also contain cladding in the form of a continuoussheath coating extending from the source to a terminus edge spacedproximally from said apex of said tapered tip toward said source by adistance of from about 2 to about 10 millimeters so that the surface ofsaid optical fiber is uncovered over the entirety of said tapered tipand over any part of a cylindrical outer surface of the fiber betweenthe terminus and the beginning of the tapered end.

The tip of the laser is substantially completely immerse into the liquidreservoir, and pulsing said laser source at a power level of from about0.1 W to about 1.5 W and at a pulse duration of from about 50 to about1000 microseconds, at a pulse frequency of from about 2 Hz to about 25Hz, and for a cycle time of from about 10 to about 40 seconds.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1a and 1b illustrate a root canal system including a main orprimary root canal and lateral and sub-lateral canals that branch off ofthe main canal. Some of these lateral canals are very small andextremely difficult to reach in order to eliminate any bacteria and/orviruses. Such lateral canals may bend, twist, change cross-sectionand/or become long and small as they branch off from the main canal,making them very difficult to access or target therapeutically.

FIG. 2 is a Scanning Electron Micrograph (SEM) clearly illustratinginternal reticular canal wall surfaces following use of the presentinvention which, as can be seen, are preserved with no burning, melting,or other alteration of the canal wall structure or loss of its porosityafter subtraction of the internal tissue. The surfaces retain highporosity and surface area and are disinfected for subsequent filling andembalming, i.e., using rubber, gutta-percha, latex, resin, etc.

FIG. 3A illustrates a more preferred approach using the currentinvention, including optical activation.

FIG. 3B is a graphical illustration of features of a laser fiber tipconfigured according to a preferred embodiment of the present invention.

FIG. 4 is a graphical illustration of a laser system according to anembodiment of the present invention.

FIG. 5 is a graphical illustration of an applicator tip of a lasersystem according to an embodiment of the invention.

FIG. 6 shows a somewhat schematic cutaway view of a tooth and healthysurrounding gum tissue.

FIG. 7 shows a somewhat schematic cutaway view of a tooth andsurrounding gum tissue including calculus deposits and partiallydiseased epithelium.

FIG. 8 shows a somewhat schematic cutaway view of a tooth andsurrounding gum tissue including a sulcus filled with a fluid mixture inwhich an instrument has been inserted for treatment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is useful for treating dental, medical, andveterinary problems; primarily dental surface and nerve preparations.The present invention uses nanotechnology and/or microtechnology indental, medical, and veterinary application during procedures thatotherwise face reoccurring infection, inefficient performance and at anincrease in expenses. The result of this invention has the potential todecrease the patient chair time by over 50%, thereby reducing the costof the procedure to the practitioner and reducing the potential forfuture failures over time.

The overall scheme according to the present invention comprises a firstsolution that is introduced into nerve tissue, typically in a tooth. Thefirst solution enlarges and porositizes the nerve tissue. Most, if notall, of the nerve is mechanically removed from the tooth by the forcesproduced by the expanding tissue on the tapered walls. A second solutionis introduced into the canal left by the optionally removed the nervetissue, which dissolves any remaining nerve tissue and debrides theaccompanying area. The porosity of the tissue allows for rapidpenetration of fluids.

The first dispensed solution comprises a carrier, a source of oxygen anda sensitizing agent. The carrier is preferably water, paste, foam and orgel or a combination of the like. The source of oxygen is preferably anoxidizing bleach agent, such as sodium hypochlorite, perborate orperoxide and the like. The sensitizing agent is preferably a nano- ormicro-structure as exemplified by fullerenes, such as nanotubes orbuckyballs, or other nanodevices (including micro-sized) capable ofsensitizing the oxygenating or activated or activatable chemical, e.g.,oxidative bleaching agent.

The sensitizing is accomplished when the first solution is applied to atargeted area directly or with mechanical, physical or other assistancesuch as mild vibrational or ultrasonic stimulation. The sensitizer isthen activated by an energy source, such as photons (light), acoustic(ultrasonic), photo-acoustic, thermo-acoustic, electromagnetic or otherphenomena that transitions the sensitizer from a ground state to ahigher energy state (singlet state). Typically the singlet state isconverted into a triplet state via an intersystem crossing mechanism.The energy difference between the triplet state and the ground state istransferred to the ground state of the. oxygen source and as a resulthighly reactive singlet oxygen is formed (type II photodynamicreaction). Presumably, the singlet oxygen expands and porositizes thenerve tissue.

The first solution can preferably include additional effectiveingredients such as surfactants to reduce the surface tension of thesolution and act as a lubricant between the nerves and the canals;antibiotics; stabilizers; polar, non-polar solvents, and the like.

This same methodology can also be used with chemical constituents otherthan singlet oxygen that are released by various forms of impartedenergy.

Preferred energy sources include, but are not limited to; sonic,ultrasonics, electromagnetic, optical, micromechanical stirring or othersimilar forms that can impart energy to the fluid or combination ofthese, which is absorbed by the sensitizer structure and creates aresultant reaction.

The most preferred embodiment of the energy source is a pulsed laserlight that is photoacoustically coupled to the first solution. The laserlight is delivered using a commercially available laser source and anoptical light fiber attached at a proximate end to the laser source andhas an application tip at the distal end. The application tip may beflat, but is preferably a beveled or tapered tip having a taper anglebetween 30 and 36 degrees. Preferably any cladding on the optic fiber isstripped from approximately 5 mm of the distal end. The taper angle ofthe fiber tip and removal of the cladding provide improved lateraldispersion of the emitted laser light and photoacoustic effect.

It was found that the photoacoustic coupling of the laser light to thefirst solution provides enhanced penetration of the first solution intothe surrounding tissue and accessory canals, thereby allowing an excitedoxygen source to reach areas of the canal system that are not accessibleto laser light alone.

In another use for the present invention is in the field of dentalcarries or cavities. X-ray identifies a carrier. The carrier is enteredusing a minimal event (small drillbit or laser drilled holes), the firstsolution is added and activated, the activated solution arrests, cleansand debrides the pathological malady without according damage to thehealthy tissue. After the first solution cleans the tooth area interioror affected carrier, the used solution is removed from the carrier, asecond X-ray may be performed with or without a radio-opaque fluid thatis introduced into the carrier to identify the extent of cleaningperformed by the first solution. The first solution may be reintroducedinto the carrier in order to further clean the interior, as necessary.After the carrier has been determined to be clean and free frominfection, it may then be filled according to current dental practiceswith only a small hole to seal on the surface.

An alternate method for introducing the first and/or second solutionswould be to use vacuum enhanced delivery methods. One such method wouldbe to apply a vacuum to the root canal, thereby removing any includedsolution, then introducing either the first or second solution into thevacuum-vacated canal, thereby using atmospheric pressure to force thesolution into small and typically inaccessible areas. Thisvacuum/pressure methodology can also be applicable to more effectivelyinfusing the filling materials.

This same methodology has the potential for use with other chemicalspecies that do not require the use of the nanotubes, but whosemolecules react with the inherent energy and whose molecules producesimilar effects to those previously mentioned above, i.e. expansion,debridement, etc.

In addition to expansion and porositizing the nerve tissue, it is foundthat the first solution also mechanically abrades, cleans and debridesthe surface of the canal or tissues. Resultant Scanning ElectronMicrographs (SEM's) show the reticular surface of the dentin to bedevoid of infection and malady and allowing for rinsed removal of thedebris elements.

FIG. 3A illustrates a more preferred approach using the invention. A.The first solution, which containing the nanotechnology, is slowlydispensed into the main root nerve and canal, 2 and 1, respectively,using a syringe 4 with nerve 2 still intact (no filing required) andallowed to penetrate into accessory nerve canals 3. B. An activatingenergy source 6, in this approach photo-acoustic, is applied. C. Thenanotechnology is activated by the energy source 6 thereby expanding thedental root nerve tissue 2 (up to 10-fold) and hydraulically forcing aportion of the nerve 2, along with a portion of the accessory nerve outof the tapered root structure and the accessory nerve out of theaccessory canals. Simultaneously, the nerve tissue 2 becomes more porousallowing more agent access to repeat the process. D. The enlarged nerve2 is optionally removed from the root canal 1. The second solution isadded with to complete tissue decomposition. E. The cavity is thenrinsed and filled and sealed (crosshatched).

As shown in FIG. 3B and FIG. 4, the most preferred embodiment of thepresent invention utilizes an energy source which is preferably a pulsedlaser energy that is coupled to a solution in such a fashion that itproduces an enhanced photoacoustic pressure wave 8. The laser light isdelivered using a commercially available laser source 12 and an opticallight fiber 14 attached at a proximate end to the laser source 12 andhas an application tip 20 at the distal end. The application tip 20 maybe flat or blunt, but is preferably a beveled or tapered tip having ataper angle between 10 and 90 degrees. Preferably any cladding 18 on theoptic fiber 14 is stripped from approximately 2-12 mm of the distal end.The taper angle of the fiber tip 20 and removal of the cladding 18provide wider dispersion of the laser energy 16 over a larger tip areaand consequently produces a larger photoacoustic wave. The mostpreferred embodiment of the application tip 20 includes a texturing orderivatization of the beveled tip 20, thereby increasing the efficacy ofthe conversion of the laser energy 16 into photoacoustic wave energywithin the solution. A coupling ferrule may be used to interchangedifferent applicator tips. It should be noted that in the presentinvention this tapered tip 20, the surface treatment, and the sheath orcladding 18 stripping is not for the purpose of diffusing or refractingthe laser light 16 so that it laterally transmits radiant optical lightenergy to the root surface. In the current invention these features arefor the sole purpose of increasing the photoacoustic wave.

Herein derivatization means a technique used in chemistry that bonds,either covalently or non-covalently, inorganic or organic chemicalfunctional group to a substrate surface.

It was found that the photoacoustic coupling of the laser energy to thesolution provides enhanced penetration of the solution into the rootcanal and accessory canals, thereby allowing the solution to reach areasof the canal system that are not typically accessible.

The photoacoustic (PA) wave is generated when the laser energytransitions from the tip (usually quartz or similar material) of thelaser device into the fluid (such as water, EDTA, or the like. Thetransmission from one medium to another is not 100% efficient and someof the light energy is turned into heat near the transition that thelight makes from one media to the other. This heating is very rapid,locally heating some of the molecules of the fluid very rapidly,resulting in molecule expansion and generating the photoacoustic wave.In a pulsed laser, a wave is generated each time the laser is turned on,which is once per cycle. A 10 HZ pulsed laser then generates 10 wavesper second. If the power level remains constant, the lower the pulserate, the greater the laser energy per pulse and consequently thegreater the photoacoustic wave per pulse.

The photoacoustic effect creates sound (pressure) waves that canpotentially propagate throughout both the media and localized structure,e.g., the main root canal and the lateral or accessory canals. Thesesound waves provide vibrational energy, which expedites the breakingloose of and/or causing cell lysis of the biotics and inorganics in theroot canal and lateral canal systems. In addition these vibrationalwaves help the propagation of the fluids into and throughout the mainand lateral canal systems.

In general, light travels in a straight line, however, in a fluid lightcan be bent and transmitted around corners, but this transmission isminimal compared to the straight-line transmissibility of light. A sonicor shock wave on the other hand is easily transmitted around corners andthrough passages in a fluid. For example, air is a fluid. If you stoodin one room and shined a bright light from that room into a hallway thatwas at right angles to that room, the intensity of the light woulddecrease the farther you go down the hallway. If you then went into aroom at the end of the hallway and went to a back corner of the room,the light might be very dim. However, if while standing at the samelocation as the light source, you yelled vocally at the hallway, youcould most likely hear the sound in the back corner of the back room.This is because sound is propagated spherically by the vibration ofmolecules instead of primarily in a straight line like light.

Although the laser light cannot turn corners easily and cannot propagateeasily into the lateral canals, the sonic wave produced by thephotoacoustic effect is easily transmitted through the lateral canals.Also, since the canals are tapered in a concave fashion, thephotoacoustic wave will be amplified as it transverses toward the end ofthe lateral canals. Since the cross-sectional area of the lateral canalsdecreases as the wave traverses toward the canal end, the amplitude ofthe wave increases much as a Tsunami wave increases as it approaches abeach where the cross sectional area of the water channel constantlydecreases.

The tip design can affect the magnitude and direction of the producedphotoacoustic wave. A tapered tip has the effect of diverting the laserenergy over the larger cone area (compared to the circular area of thestandard tip) and thereby creating a larger photoacoustic wave. The sameapplies to any stripped sheath section of the tip.

Testing Using a MEMS Pressure Sensor:

A small plastic vial was fitted with a fluid connection (bottom of vialat right angles to axis of vial) that was close coupled hydraulically toa miniature MEMS piezo-resistive pressure sensor (Honeywell Model24PCCFA6D). The sensor output was run through a differential amplifierand coupled to a digital Oscilloscope (Tektronics Model TDS 220). Thismodel oscilloscope will hold a trace on the screen and allow a digitalimage to be taken of the trace. The vial and sensor were filled withwater. The laser tip was submerged below the fluid level in the vial andfired (laser frequency was 10 HZ) at various power setting. A trace wasrecorded of the resulting photoacoustic pressure waves.

A 170% increase in the photoacoustic wave was observed for the taperedand stripped tip versus the blunt-ended tip. A 580% increase in thephotoacoustic wave was observed for textured (frosted) tapered/strippedtip versus the standard blunt-ended tip. The tapered tip has a greaterexposed area than the blunt straight tip. The fiber optic is coated witha polyamide sheath, which reflects the laser beam internally, notallowing it to escape and propagating the laser energy down the fiber tothe tip. On the straight or blunt-ended tip, the exposed area is thecircular cross-sectional area of the end of the tip. On the tapered tipand textured tip the exposed area is the area of the tapered cone, whichis greater than the exposed area of the blunt straight tip. Thisinvention is on the ability of these features to increase thephotoacoustic wave not to refract or redirect the radiant opticalproperties of the laser energy. In fact such radiant light energy canfuse the root canal wall surface making it impossible to clean anddebride the small passages behind the fused areas.

During a previous experiment, fluid was placed into a Dampen dishlocated on a Formica surface. The laser tip was placed into the fluidand fired repetitively. The photoacoustic wave vibrated the Dampen dishon the Formica surface making an audible sound. For a specific tip thisaudible sound increased with an increasing power level of the laser.This implies that the audible sound is somewhat proportional to theamplitude of the photoacoustic wave. This was verified by placing asound level meter one inch away from the Dampen dish and recording thedB level. Next, the laser power level was held constant and the tip waschanged. The tapered and stripped sheath tip produced a greaterphotoacoustic wave than the standard straight or blunt-end tip. Atapered and stripped tip was then frosted or etched. This tip was testedand showed a greater photoacoustic wave generated than the non-frostedversion. This was verified to be true at three different power levels.It would appear that since the power level was held constant, thephotoacoustic wave amplitude would also be proportional to the exposedarea and the surface treatment.

An increase in photoacoustic wave generation was seen by stripping thepolyamide sheath away for 2-12 mm from the tapered end. Although laserlight is coherent and travels in a straight line, some light bounces offof the polyamide sheath at an angle. As this light travels down thelight path it continues bouncing off of the inside of the polyamidesheath and will eventually exit at an angle to the sheath once thesheath stops and exposes a non sheathed section. Therefore, some of thelaser energy would also exit where the polyamide sheath has beenremoved, just upstream of the tapered tip. A tip with the sheath removedfor 2 to 12 mm directly upstream of the tapered section was placed inthe above-mentioned test set up.

The photoacoustic wave will propagate primarily perpendicular to theexposed surface and secondarily spherically with respect to the exposedsurface. The standard straight end tip would have the PA wavepropagating primarily in line with the tip. The tapered tip produced PAwave would be primarily propagated in a more lateral pattern. Thetapered tip with the shinned sheath would propagate the PA wave in amore spherical pattern than the other two.

The standard straight blunt end tip would be less desirable because itdirects the photoacoustic wave toward the apical end of the tooth andwould have more propensities to drive the fluid from the nerve hole inthe apical end and outward into the gum which could create medicalcomplications. Since there may be lateral or accessory canals anywherealong the main root canal, it is more desirable to have a spherical wavedistribution to direct waves to as many lateral canals as possible.Therefore the tapered tip with the skinned sheath produces a moredesirable effect within the tooth.

Resultant Scanning Electron Micrographs (SEM's) show the reticularsurface of the dentin to be devoid of infection and malady and allowingfor rinsed removal of the debris elements.

A method and apparatus according to a preferred embodiment of thepresent invention uses a subablative energy source, preferably a pulsinglaser, to produce photoacoustic energy waves in solutions dispensed in aroot canal to effectively clean the root canal and lateral canals. Inthe context of this application, the term “subablative” is used to referto a process or mechanism which does not produce or cause thermalenergy-induced destruction of nerve or other native tooth structure,material or tissue, namely, that does not carbonize, burn, or thermallymelt any tooth material. The pulsing laser in the inventiveconfiguration of a preferred embodiment induces oscillatingphotoacoustic energy waves which emanate generally omnidirectionallyfrom adjacent the exposed length of an applicator tip where light energyis caused to exit the surface of optical fiber material in manydirections/orientations into adjacent fluid medium from a light energysource maintained at a relatively low power setting of from about 0.1 tono more than about 1.5 watts in order to avoid any ablative effects.

According to one embodiment of the present invention, a tooth is firstprepared for treatment in a conventional manner by drilling a coronalaccess opening in the crown of the tooth to access the coronal or pulpchamber and associated root canal. This may be performed with a carbideor diamond bur or other standard approaches for preparation of a toothfor root canal treatment known in endodontic practice after which theupper region above the entry of the canal into the chamber is generallyemptied of pulp and other tissue. Thereafter, a first solution is slowlydispensed into the chamber, such as by use of a syringe or otherappropriate mechanisms, with a small amount seeping and/or injected downinto the individual root canals containing the as-yet unremoved nervesand other tissue. The first solution is preferably dispensed in anamount sufficient to fill the chamber to adjacent the top of thechamber. In other embodiments, portions of the nerve and other tissue inthe canals may be removed using a broach or other known methods forremoving a nerve from a root canal before the first solution isdispensed into the chamber and down into the root canals. In someembodiments, only a single solution may be used, although multiplesolutions or mixtures may also be used as explained in more detailbelow.

The first solution preferably includes a compound containing moleculeswith at least one hydroxyl functional group and/or other excitablefunctional groups which are susceptible to excitation by a laser orother energy source in the form of rapidly oscillating photoacousticwaves of energy to assist with destructive subablative disintegration ofroot canal nerve tissue. It has been observed that certain fluids whichdo not contain excitable groups, such as xylene, do not appear toproduce the desired photoacoustic wave when an energy source has beenapplied. In one embodiment of the invention, the first solution is astandard dental irrigant mixture, such as a solution of water andethylenediamine tetraacetic acid (EDTA), containing hydroxyl or otherexcitable groups. In other embodiments of the invention, thehydroxyl-containing solution may be distilled water alone. In otheralternate embodiments, solutions containing fluids other than water maybe used, or various pastes, perborates, alcohols, foams, chemistry-basedarchitectures (e.g., nanotubes, hollow spheres) and/or gels or acombination of the like may be used. Additionally, various otheradditives may be included in the solution. For example, and not by wayof limitation, the first solution may include agents energizable byexposure to energy waves propagated through the solution from adjacentthe fiber. These include materials selected from the group consisting ofhydrogen peroxide, perborates, hypochlorites, or other oxidizing agentsand combinations thereof. Additional additives believed to beenergizable in the solution include materials selected from the groupconsisting of reducing agents, silanols, silanating agents, chelatingagents, chelating agents coordinated or complexed with metals (such asEDTA-Calcium), anti-oxidants, sources of oxygen, sensitizing agents,catalytic agents, magnetic agents and rapidly expanding chemical,pressure or phase change agents and/or combinations of the like. Thesolution may also include dispersions or mixtures of particlescontaining nano- or micro-structures, preferably in the nature offullerenes, such as nanotubes or bucky balls, or other nanodevices(including micro-sized devices) capable of sensitizing or co-acting withoxygenating, energizable, or activatable components in thesolution/mixture, such as oxidative bleaching or other oxygenatedagents. Various catalytic agents may be titanium oxide or other similarinorganic agents or metals. The first solution may also includeadditional effective ingredients such as surfactants or surface activeagents to reduce or otherwise modify the surface tension of thesolution. Such surface active agents may be used to enhance lubricationbetween the nerves and other intracanal tissue and the canals wall, aswell as antibiotics; stabilizers; antiseptics; anti-virals; germicidals;and polar or non-polar solvents; and the like. It is especiallypreferred that all materials used in the system be bio-compatible andFDA and otherwise approved, as necessary, for use in dental procedures.The amounts of any of the foregoing and other additives are generallyvery small in the order of a few percent by weight or only smallfractions of percents. The majority of the solution/mixture ispreferably water, preferably sterile triple distilled water foravoidance of undesirable or unaccounted for ionic effects.

An activating energy source is applied to the first solution containedin the coronal pulp chamber. In a preferred embodiment, the activatingenergy source is a pulsing laser 10. The laser light energy 16 isdelivered using a laser source 12 and an optical light fiber 14 attachedat its proximate end to a laser source 12 and having an applicator tip20 adjacent its distal end. The optical fiber 14 preferably has adiameter of from about 200 microns to about 400 microns. The diametershould be small enough to easily fit into the coronal pulp chamber and,if necessary, into a root canal itself, but large enough to providesufficient energy via light carried therein to create a photoacousticeffect and to prevent avoidable leakage of light or loss of energy anddamage to the tooth or the fiber tip. In a preferred embodiment, thelaser source is a solid state laser having a wavelength of from about700 nm to about 3000 nm, such as NdYAG, ErYAG, HoYag, NdYLF, TiSapphire, or ErCrYSGG laser. However, other suitable lasers sources maybe used in various embodiments.

An appropriately dimensioned laser applicator tip 20 is preferablyplaced into the coronal chamber until it is at least fully immersed inthe first solution. By “fully immersed” it is meant liquid level is evenwith the edge of the cladding or other covering on the optical fiber 18.Preferably, the distal most edge of any cladding or covering 18 on theoptic fiber 14 adjacent the tip is spaced approximately 2-10 mm from thedistal end of the distal end tip or end of the fiber, most preferablyabout 5 mm therefrom. As a result, up to about 10 mm and most preferablyabout 5 mm of the distal end of the fiber is uncovered. Preferably, allor substantially all of the length of this uncovered part of the tip endis immersed. If the uncovered part of the applicator tip is not fullyimmersed, sufficient energy may not be transferred to the fluid sincelight will be permitted to escape to the environ above the liquidsurface. Accordingly, it is believed that spacing the distal-most oroutermost end edge of the cladding more than about 10 mm should beavoided, as that can diminish the effectiveness of the system. In someapplications, it may be necessary to provide a dam and reservoir aroundand above the opening in the tooth in order to increase the volume andlevel of fluid available for immersion of the uncovered area of the endof the fiber. The larger liquid volume and deeper immersion of theuncovered area of the tip end is believed to enable application ofsufficient energy levels to produce the desired photoacoustic waveintensity in such instances. Such instances may include, for example,smaller teeth such as upper/lower centrals or teeth that are fracturedoff. In certain applications where a dam or reservoir is used it may bedesirable to use a laser tip with more than 10 mm of space between thetip end and the cladding due to the larger volume of fluid.

It is a feature of the invention in a preferred embodiment that thedistal-most end of the applicator tip be tapered to and end point, i.e.that the distal end have a “tapered tip” 22. Most preferably, thetapered tip has an included taper angle of from about 25 to about 40degrees. The applicator tip 20 is therefore preferably not a focusinglens configured to concentrate light to a point in space away from thetip end. Such a configuration is believed to cause an ablative effectdue to the high thermal energy created by the laser light focused to apoint. Rather, the taper angle of the tapered fiber tip 22 and rearwardspacing of the end of the cladding from the tip end in accordance withpreferred embodiments of the invention are believed to enable arelatively wide dispersion of the laser energy for emission from arelatively large surface area of the tip all the way back to the edge ofthe cladding, not merely from the end of the laser fiber. An objectiveis to emit laser light generally omnidirectionally from the sides 24 andfrom the tapered area 22 of the tapered applicator tip, andconsequently, to produce a larger or more omnidirectional photoacousticwave propagating into surrounding liquid and adjacent material fromsubstantially the entire exposed surface of the fiber optic quartzmaterial. Among other things, this avoids and preferably eliminates anyablative effects associated with higher levels of focused or refractedradiant laser energy. The tip design in accordance with the invention isselected to provide a magnitude and direction of the photoacoustic wavein the surrounding fluid medium that exhibits a relatively sharp or highrise time at the leading edge of each pulse and which propagates throughthe fluid generally omnidirectionally from the exposed area of the endof the fiber. Accordingly, a tapered tip according to the invention hasthe effect of dispersing the laser energy over the larger uncovered conesurface area and the rearwardly extending cylindrical wall surface(compared to a two dimensional generally flat circular surface area of astandard tip), thereby creating a much larger area through which theleading edges of the successive photoacoustic waves can propagate. Insome embodiments, the exposed area of the fiber adjacent the tip end mayinclude a texturing, such as frosting or etching, to increase thesurface area and angular diversity of light emission for an even morecomprehensive coverage of the photoacoustic wave energy within thesolution and adjacent tissue.

When applying the laser to the first solution, applicants havediscovered that it may be important to apply the laser energy to thesolution so as to limit the creation of thermal energy. In the presentinvention, after the applicator tip is immersed in the first solution,laser energy is preferably applied to the first solution usingsubablative threshold settings, thereby avoiding any thermal-inducedcarbonization, melting, or other effects caused by a temperature riseabove about 5° C. in the dentin walls of the canal, apical portions ofthe tooth, or surrounding bone or tissue caused by the generation ofsignificant thermal energy in the canal area or wall due to the ablativepower settings used in prior attempts to perform root canal therapy withlasers. The practice of the present invention in accordance with itspreferred embodiments causes an observable temperature rise in thesolution of no more than a few degrees Centigrade and, as a result, nomore than a few degrees Centigrade elevation, if any, of the dentin walland other adjacent tooth structure and tissue. This is far below thestandard constraint of avoiding any exposure of such material and tissueto more than 5° C. increase in temperature for any significant period oftime to avoid permanent damage in the same.

The inventors have found that relatively low power settings of fromabout 0.1 watt to about 1.5 watt and with a laser pulse duration of fromabout 100 nanoseconds to about 1000 microseconds, with a pulse length ofabout 50 microseconds most preferred, produces the desired photoacousticeffect without heating the fluid or surrounding tissue to produce anyablative or other thermal effect within or adjacent the root canal. Afrequency of from about 5 to 25 Hz is preferred and a frequency of about15 Hz is believed to provide optimal potentiation of harmonicoscillation of pressure waves in the fluid medium to disintegrate nerveand other tissue within the canal.

The particular preferred power level found to produce the idealphotoacoustic wave has a relationship to the approximate root volume ofa particular tooth. The following chart (Table 1) shows what are believeto be preferred ranges of power levels for treatment of root canals indifferent types and sizes of teeth in accordance with the invention.

TABLE 1 Preferred Power Levels for Various Tooth Types Approx. AverageRange of Preferred Tooth Type Root Volume (μL) Power Levels (watts)Molar 177 0.5 to 1.5 Pre Molar 88 0.5 to 1.0 Cuspid 67  0.5 to 0.75Laterals 28 0.25 to 0.5  Centrals 28 0.25 to 0.5  Lower Centrals 28  0.1to 0.25

When the laser is immersed in the first solution, the laser is pulsedfor a time preferably ranging from about 10 seconds to about 40 seconds,most preferably about 20 seconds. If the laser is pulsed for longer thanabout 40 seconds, excessive thermal energy can begin to develop in thefluid, potentially leading to deleterious heating effects in and aroundthe tooth as described above. It has been found rather surprisingly thatpulsing under the parameters of the invention causes a measurabletemperature rise in the fluid medium of no more than a few degreesCelsius, if any, while still utterly destroying and/or disintegratingall nerve, pulp, and other tissue within the canal that also is observedto hydraulically self-eject from the canal during pulsing.

After the laser has been pulsed in the first solution, the firstsolution is allowed to stabilize and then laser pulsing treatment may berepeated again in the same or a different solution. In certainembodiments, the solution may be removed between repetitions of pulsingcycles of the laser to remove debris more gradually and to avoid anydevelopment or transfer of heat energy into the dentin surrounding wallor other adjacent structure. The coronal chamber and canal may beirrigated with a standard dental irrigant and solution may then bereinserted into the coronal chamber to perform an additional laserpulsing treatment. While any number of pulsing phases or cycles can berepeated, it is believed that a fully effective removal of all materialwithin the canal can be achieved in less than about seven cycles.

To assist dentists in performing root canal treatments according to thepresent invention, a photoacoustic activity index has been developedwhich provides relationships between the various parameters, machinesetting, and the like which have been found to be important in thepractice of the inventive procedure. Factors which appear important inthe practice of the invention include the power level, laser pulsefrequency, the pulse duration, the proportion of average excitablefunctional groups per molecule in the first solution, the diameter ofthe laser optical fiber, the number of pulsing cycles repeated incompleting an extirpation procedure, the duration of each cycle, theviscosity of the first solution, and the distance between the tip andthe end of the cladding. Coefficients have been determined which relatedeviations of certain of the above factors from what is believed to bethe ideal or the most preferred factor value. Tables of thesecoefficients are shown below:

Approx. Average Preferred Range of Power Density Root Volume PowerLevels Coefficient Tooth Type (ul) (watts) (DPD) Molar 177 0.5 to 1.5 1Pre Molar 88 0.5 to 1.0 1 Cuspid 67  0.5 to 0.75 1 Laterals 28 0.25 to0.5  1 Centrals 28 0.25 to 0.5  1 Lower Centrals 28  0.1 to 0.25 1

Frequency Coefficient Pulses per Second C(fq) (Value in HZ) 0.4  2 HZ0.6  5 HZ 0.9 10 HZ 1 15 HZ 0.5 20 HZ 0.2 25 HZ

Pulse Duration Coefficient Pulse Duration Value in micro sec C(pw) (μs)1 <50 0.9 50 0.7 100 0.3 150 0.2 200 0.1 1000

Hydroxyl Coefficient Average quantity of excitable groups C(hy) perfluid molecule 1 >2 0.9 2 0.7 1 0.5 Part or Mixture 0 none

Fiber Diameter Coefficient Fiber Diameter Value in C(fd) microns0.8 >400 1 400 0.8 320 0.5 200 0.3 <200

Repetition Cycle Coefficient Repetition Cycles C(rp) (repetitions)0.3 >7 0.5 6 0.7 5 1 4 0.9 3 0.6 2 0.3 1

Cycle Duration Coefficient Cycle Duration C(sa) (Value in seconds)0.2 >40 0.6 40 0.9 30 1 20 0.5 10 0.2 <10

Viscosity Coefficient Fluid Viscosity C(vs) (Centipoise) 1 <1 0.9 10.1 >500 0.05 >1000

Cladding Separation Distance Between Terminus of Cladding LengthCoefficient and Apex of Tip Value in millimeters C(sl) (mm) 0.4 2 0.6 30.9 4 1 5 0.9 >5 0.3 >10

A practitioner may input coefficients from the above tables correlatingto equipment, setting, and material parameters into the followingequation:Photoacoustic Activity Index (“PA”Index)=DPD×C(fq)×C(pw)×C(hy)×C(fd)×C(rp)×C(sa)×C(vs)×C(sl)

If the resulting PA Index value is greater than about 0.1, morepreferably above about 0.3, then the equipment and materials maygenerally be acceptable to produce an effective photoacoustic wave fordisintegration and substantially complete and facile removal of all rootcanal nerve, pulp, and other tissue from within the canal. If the PAIndex is below about 0.1, it may indicate a need to modify one'sequipment setup, setting, and method parameters in order to more closelyapproach the desired PA index of 1 or unity.

Using the invention parameters and procedures, root canal tissue andother material to be removed or destroyed is not believed to be removedor destroyed via thermal vaporization, carbonization, or other thermaleffect due primarily to exposure to high temperatures, but ratherthrough a photoacoustic streaming of and other activities within liquidsin the canal which are laser activated via photon initiatedphotoacoustic streaming (PIPS). A photoacoustic wave with a relativelyhigh leading edge is generated when the laser light transitions from theexposed surface of the fiber optic material into the solution. The laserlight is believed to create very rapid and relatively intenseoscillations of waves through the solution emanating from the interfaceof the exposed surface of the fiber optic and the surrounding liquid.The rapid, intense microfluctuations in the light energy emitted isbelieved to cause rapid excitation and/or expansion and de-excitationand/or expansion of hydroxyl-containing molecules adjacent the exposedsurface of the fiber generating, among other things, photoacoustic wavesof energy which propagates through and into the root canal system andoscillates within the system. These intense photoacoustic waves arebelieved to provide substantial vibrational energy, which expedites thebreaking loose of and/or cell lysis and other effects to bring about arapid and facile degradation/disintegration of substantially all tissuein the root canal and lateral canal systems immersed in the solution.The pulsing photoacoustic energy waves in combination with the chemistryof the fluid also is believed to cause intense physically disruptivecycling of expanding and contracting of nerve and other tissue whichporositizes, expands, and ultimately disintegrates the nerve and othertissue in the canal without any significant thermally inducedcarbonization or other thermal effects of the same so that the resultingsolution/mixture containing nerve and other tissue remains is observedto be self-ejected or basically “pumped” by a hydraulic effect out ofthe canal.

The photoacoustic effect creates energy waves that propagate throughoutthe fluid media in the main root canal and into the lateral canals,thereby cleaning the entire root system. The use of a substantiallyincompressible fluid medium causes the waves produced by thephotoacoustic effect to be instantly transmitted through the lateralcanals. Also, since the canals are tapered in a concave fashion, thephotoacoustic wave is believed to be amplified as it transverses towardthe end of the lateral canals for further intensification of thedestruction towards apical or cul de sac areas.

In certain embodiments of the invention, a second dissolution solutionmay be added to the canal after treatment with the energy source/firstsolution. This dissolution solution chemically dissolves and/ordisintegrates any remaining nerve structure or other debris that mayremain in the main canal or in any lateral canals. Preferred dissolutionsolutions include hypochlorite, sodium hypochlorite, perborate, calciumhydroxide, acetic acid/lubricant/doxycycline and other like nerve tissueor matrix dissolving substances such as chelating agents (EDTA) andinorganic agents such as titanium oxides.

Finally, after desired tissue has been removed from the tooth interior,the canal may be irrigated to remove any remaining debris and remainingsolution, and then obturated with a material of choice, such as guttapercha, root canal resin, etc., according to standard practices in theindustry.

Qualitative experimentation was performed placing a fluid into a Dampendish located on a Formica surface. The laser applicator tip was placedinto the fluid and fired repetitively. The photoacoustic wave vibratedthe Dampen dish on the Formica surface making an audible sound. For aspecific tip this audible sound increased with an increasing power levelof the laser. This was verified by placing a sound level meter one inchaway from the Dampen dish and recording the dB level. This implies thatthe power level is proportional to the amplitude of the photoacousticwave. Next, the laser power level was held constant and the tip waschanged. The tapered tip and a tip with a stripped sheath produced agreater photoacoustic wave than the standard flat tip. A tapered,stripped tip was then frosted or etched. This tip was tested and showeda greater photoacoustic wave generated than the non-frosted version.This was verified to be true at three different power levels. It wouldappear that since the power level was held constant, the photoacousticwave amplitude would also be proportional to the exposed area and thesurface treatment.

In a quantitative investigation of the applicator tip a MEMS Pressuresensor was utilized to measure the photoacoustic wave amplitude. Thistesting has shown a dramatic increase in the photoacoustic wavepropagation caused by changes in the geometry and texturing of the tip.The inventors have also discovered that stripping of the cladding fromthe end of the applicator tip results in increases in the photoacousticwave effect. In this regard, a small plastic vial was fitted with afluid connection that was close coupled hydraulically to a miniatureMEMS piezo-resistive pressure sensor (Honeywell Model 24PCCFA6D). Thesensor output was run through a differential amplifier and coupled to adigital Oscilloscope (Tektronics Model TDS 220). The vial and sensorwere filled with water. Laser tips having varying applicator tipconfigurations were fully submerged below the fluid level in the vialand fired at a frequency of 10 HZ. The magnitude of the photoacousticpressure waves was recorded by the pressure sensor.

A 170% increase in pressure measured from generation of thephotoacoustic waves was observed for the tapered tip versus the standardblunt-ended tip. A 580% increase in pressure measured from generation ofthe photoacoustic wave was observed for textured (frosted) tapered tipsversus the standard blunt-ended tip. Rather than emitting in asubstantially linear direction, the frosting disperses the lightomnidirectionally causing excitation and expansion of more fluidmolecules.

An increase in photoacoustic wave generation was seen by stripping thepolyamide sheath away from about 2 mm to about 10 mm from the taperedend. Although laser light is coherent and typically travelssubstantially in a straight line, some light bounces off of thepolyamide sheath at an angle. As this light travels down the light pathit continues bouncing off of the inside of the polyamide sheath and willeventually exit at an angle to the sheath once the sheath stops andexposes a non sheathed section. Therefore, some of the laser light wouldalso exit where the polyamide sheath has been removed, upstream of thetapered tip end. A tip with the sheath removed for 2 to 10 mm directlyupstream of the tapered section was placed in the above-mentioned testset up and showed markedly better production of photoacoustic waves.

In various other embodiments of the invention, energy sources other thanlasers may be used to produce the photoacoustic waves including, but notlimited to, other sources of light energy, sonic, ultrasonic,photo-acoustic, thermo-acoustic, micromechanical stirring, magneticfields, electric fields, radio-frequency, and other exciter mechanismsor other similar forms that can impart energy to a solution. Some ofthese sources penetrate the tooth structure externally. Additionalsubablative energy sources may be used to create other types of pressurewaves in a solution, such as chemoacoustic waves (shock waves created byrapid chemical expansion creating shock and pressure waves). Such wavescan be created for example by loading the nanoparticles with a chemicalthat expands rapidly upon excitation, coating nanoparticles with a hardshell (e.g., polyvinyl alcohol), and activating the chemistry with anenergy source such as optical, ultrasonic, radio-frequency, etc. As theactivating chemical expands, pressure builds up in the hard shell, whenthe shell bursts it creates a shock wave that can propagate throughoutthe fluid similar to a photoacoustic wave. Additionally, a photoacousticwave can be the activating energy source for producing the chemoacousticwave.

Further, the present invention may be used for various procedures otherthan root canal treatment, such as for treatment of dental caries,cavities or tooth decay. Additionally, the present invention may beusable for treatments of bone and other highly networked material whereinfection is problematic, e.g. dental implants, bone infection,periodontal disease, vascular clotting, organ stones, scar tissues, etc.Adding a tube structure around the tip which might be perforated andwill allow introduction of a fluid around the tip that will allow thephotoacoustic waves to be directed into more difficult areas that do notcontain fluid volume such as periodontal and gum tissue. This would beconsidered a type of photoacoustic transmission tube. This applicationprocess may also be used in other soft tissue applications where it isnecessary to expand the diseased tissue or material to allow more rapidaccess and penetration to healing agents, chemicals or biologicals;i.e., antibiotics, peptides, proteins, enzymes, catalysts, genetics(DNA, mRNA or RNA or derivatives) or antibody based therapeutics orcombinations thereof. In some cases, the present methodology may be usedto rapidly dissolve or destroy diseased tissue areas. Additionally, thepresent invention may be used to expand diseased tissue in an abscess,allowing for extremely rapid and efficient penetration of healing orbiological agents. The porosity created in the tissue by photoacousticwaves may allow for rapid infusion with the subsequent chemical speciesthat can impose destruction, healing or cleaning or a combination ofthese events. The speed of this healing action may allow medicalprocedures that currently are not viable because of extensive timerequired for standard healing processes, i.e., sometimes adjacent tissueis infected because the original infection cannot be controlled morerapidly than the infection propagates. In this case, expanding thediseased tissue to enhance porosity may allow near instantaneous accessfor the medication, e.g., antibiotic or other agents.

Furthermore, the present invention may be applied to begin, construct orstage the activation of cells and/or tissues, including the area oftransplantation and use in stem or primordial cells accentuation, theirattachment and/or stimulation for growth and differentiation. Thepresent invention is also believed to be usable to activate cells, e.g.,progenitor, primordial or stem cells, to promote inherent nascent boneor tissue growth and differentiation, as well as in transplantationwhere stem or primordial cells are accentuated in their attachment andstimulated for growth and differentiation.

In one of the alternate embodiments of this invention, nanotubes orother micro-structures can be moved around in a therapeutic fluid byapplying a magnetic field. An alternating or pulsed magnetic field couldimpart significant motion and stirring of the therapeutic fluid. Sincethe field would penetrate the entire tooth, the stirring action wouldalso occur throughout the lateral or accessory canal system. Thesemoving micro-particles would also act as an abrasive on any bacteria,virus, nerve material, or debris within the canal system. The effectwould be a more thorough circulation of the fluid throughout the canalsystem to provide superior cleaning and debridement of the canal system.Magnetic material can also be inserted into, adsorbed onto, or absorbedinto the nanotube or other microstructure increasing its magneticmoment.

TiO₂ or other similar compounds can be activated and made bactericidalby exposing them to UV light or by inserting them in an electric field.Once excited these can destroy bacteria and other organic compounds suchas remaining nerve tissue. Such compounds can be part of a therapeuticand can be activated by a UV light source pointed toward the therapeuticfluid, a UV source dipped into the fluid, or a UV laser source. TheseTiO₂ or other similar compounds can also be activated by an alternatingor pulsed electric field. One means to supply such an electric fieldcould be by an external device that would bridge the tooth. Since thefield propagates throughout the entire tooth it would also react TiO₂ orother similar compounds within the accessory or lateral canals. Thisaction could also be combined with the micro-particle based motionaction mentioned above. This combination would more thoroughly clean anddebride the canals. Since electric fields are generated externally andpenetrate the entire root structure they could be used several months oron a yearly basis after the tooth is sealed to reactivate the titaniumoxide and its bactericidal properties.

The foregoing description of preferred embodiments for this disclosurehas been presented for purposes of illustration and description. Thedisclosure is not intended to be exhaustive or to limit the variousembodiments to the precise form disclosed. Other modifications orvariations are possible in light of the above teachings. The embodimentsare chosen and described in an effort to provide the best illustrationsof the principles of the underlying concepts and their practicalapplication, and to thereby enable one of ordinary skill in the art toutilize the various embodiments with various modifications as are suitedto the particular use contemplated. All such modifications andvariations are within the scope of the disclosure as determined by theappended claims when interpreted in accordance with the breadth to whichthey are fairly, legally, and equitably entitled.

What is claimed is:
 1. A method for cleaning a root canal of a tooth,the method comprising: delivering a treatment liquid into the rootcanal; inserting a tip of an optical fiber into the treatment liquidwithin the root canal, the optical fiber extending along a fiber axis,the tip comprising a conical tip that emits at least a portion of laserlight laterally outwardly relative to the fiber axis; operating a lasersource at a power level of at least 0.5 W to generate the laser lighthaving a wavelength of at least 1500 nm; pulsing the laser light alongthe optical fiber to the tip; directing at least a portion of the laserlight laterally outwardly relative to the fiber axis into the treatmentliquid, the laser light emanating from the tip having sufficient powerto create photoacoustic waves in the treatment liquid of sufficientvibrational energy to remove at least organic material from a portion ofa wall of the root canal; and withdrawing the tip from the root canal.2. The method of claim 1, further comprising distributing the treatmentliquid throughout the root canal with the vibrational energy of thephotoacoustic waves.
 3. The method of claim 1, wherein the root canalcomprises at least a main root canal and a plurality of accessory canalsthat branch from the main root canal, the method further comprisinginserting the tip of the optical fiber into the treatment liquid in themain canal, and propagating the photoacoustic waves throughout the mainroot canal and the accessory root canals to remove at least organicmaterial from both the main root canal and one or more of the accessoryroot canals without the tip of the optical fiber being inserted into anyof the accessory canals.
 4. The method of claim 1, wherein directing atleast a portion of the laser light laterally outwardly relative to thefiber axis into the treatment liquid comprises directing most of thelaser light in a direction that is non-parallel to the fiber axis. 5.The method of claim 1, wherein inserting the tip of the optical fibercomprises providing the optical fiber having a cladding stripped from adistal end of the optical fiber by a distance in a range of 2 mm to 12mm.
 6. A method for cleaning a root canal of a tooth, the root canalcomprising a main root canal and a plurality of accessory canals thatbranch from the main root canal, the method comprising: delivering atreatment liquid into the root canal; inserting a tip of an opticalfiber into the treatment liquid within the main root canal, the opticalfiber extending along a fiber axis, the tip comprising a tapered tip;operating a laser source at a power level of at least 0.5 W to generatelaser light having a wavelength of at least 1500 nm; pulsing the laserlight along the optical fiber to the tip; and directing at least aportion of the laser light laterally outwardly relative to the fiberaxis into the treatment liquid, the laterally directed light havingsufficient power to create photoacoustic waves in the treatment liquidof sufficient vibrational energy to remove at least organic materialfrom both the main root canal and one or more of the accessory rootcanals, without the tip of the optical fiber being inserted into any ofthe accessory canals.
 7. The method of claim 6, wherein directing the atleast a portion of the laser light laterally outwardly comprisesproviding a shape for the tip which tapers radially inwardly anddistally.
 8. The method of claim 6, wherein directing at least a portionof the laser light laterally outwardly relative to the fiber axis intothe treatment liquid comprises directing most of the laser light in adirection that is non-parallel to the fiber axis.
 9. The method of claim6, wherein inserting the tip of the optical fiber comprises providingthe optical fiber having a cladding stripped from a distal end of theoptical fiber by a distance in a range of 2 mm to 12 mm.
 10. A methodfor cleaning a root canal of a tooth, the method comprising: deliveringa first treatment liquid into the root canal; inserting a tip of anoptical fiber through an opening of the tooth into the first treatmentliquid within the root canal, the optical fiber extending along a fiberaxis, the tip comprising a conical tip without a focusing lens;operating an ErCrYSGG laser source at a power level in a range of 0.1 Wto 1.5 W and at a pulse duration in a range of 50 microseconds to 1000microseconds to generate laser light; pulsing the laser light along theoptical fiber to the tip; directing at least a portion of the laserlight laterally outwardly relative to the fiber axis into the firsttreatment liquid, the laser light emanating from the tip havingsufficient power to create photoacoustic waves in the first treatmentliquid of sufficient vibrational energy to remove at least organicmaterial from a portion of a wall of the root canal without carbonizing,burning, or thermally damaging dentin along the wall of the root canalwith the tip immersed within the first treatment liquid; withdrawing thetip from the root canal; and after directing at least a portion of thelaser light laterally outwardly relative to the fiber axis into thefirst treatment liquid, delivering a second treatment liquid into theroot canal, inserting the tip through the opening into the secondtreatment liquid, further operating the ErCrYSGG laser source togenerate laser light, further pulsing the laser light along the opticalfiber to the tip, and directing at least a portion of the laser lightlaterally outwardly relative to the fiber axis into the second treatmentliquid to generate photoacoustic waves in the second treatment liquid.11. The method of claim 10, further comprising operating the ErCrYSGGlaser source at a cycle time in a range of 10 seconds to 40 seconds. 12.The method of claim 10, wherein delivering the second treatment liquidcomprises providing the second treatment liquid to be different from thefirst treatment liquid.
 13. The method of claim 10, wherein insertingthe tip of the optical fiber through the opening of the tooth into thefirst treatment liquid comprises providing the optical fiber having acladding stripped from a distal end of the optical fiber by a distanceof no more than 10 mm.
 14. The method of claim 10, wherein pulsing thelaser light or further pulsing the laser light involves delivering powerat a level sufficient to remove the organic material from the wall ofthe root canal without elevating a temperature of the tooth or adjacenttissue by more than 5° C.
 15. The method of claim 10, wherein operatingthe ErCrYSGG laser source or further operating the ErCrYSGG laser sourcecomprises operating the ErCrYSGG laser source at a pulse duration in arange of 100 microseconds to 1000 microsecond.
 16. The method of claim10, wherein inserting the tip of the optical fiber through the openingof the tooth into the first treatment liquid comprises providing theoptical fiber having a diameter in a range of 200 microns to 400microns.
 17. The method of claim 10, further comprising removing thefirst treatment liquid before delivering the second treatment liquidinto the root canal.